Why did Lavan remove even the spotted and blotched he-goats?
Ramban: Lavan took into account the possibility that the female sheep may give birth to spotted and blotched sheep, like their fathers.
Malbim: Lavan was not supposed to take anything for himself. He distorted Yakov's words to mean that Lavan will take what already has such appearances, and Yakov will get only what is born like this in the future.
Why did Lavan remove even those with white marks on their ankles (Akudim), even though Yakov had not mentioned them?
Ramban: To reduce the chances of the sheep conceiving babies with white marks on them.
Ohr ha'Chayim 1 (32): Yakov did not want to receive the Akudim, for then he would need to remove them from Lavan's flock, and then there is nothing white to cause the flock to give birth to spotted babies. He never intended for any trickery. Lavan removed also Akud and anything with any white, so nothing with any white would be born. Yakov was forced to peel sticks [to enable babies to be born with white]. He took for himself the Akudim, for Lavan revealed that they are Yakov's.
Malbim: Lavan was preparing to change Yakov's wages. He took Akudim among male goats, so he can claim later (if it will benefit him) that this was because Yakov receives those born Akudim. He took Nekudim among females, so he can claim later that this was because Yakov receives those born Nekudim. If Yakov will refute him based on the other gender, it will be a Safek, and Lavan need not give amidst Safek.
When Yakov presented his condition, he volunteered to remove all the specified animals that were already in Lavan's flocks. Why did Lavan remove them.
Oznayim la'Torah: Yakov volunteered to remove the specified lambs and kid-goats from the flocks so as not to mix them up with those that would subsequently be born that year. Lavan opted to remove, not only the lambs and kid-goats, but also the sheep and the goats 1 from the flocks; in fact he removed all sheep that contained black and all goats that contained white, 2 having in mind that all the remaining sheep will give birth to black lambs and all the remaning goats, to white kids - all of which will belong to him, leaving Yakov with nothing. 3
Lavan asked Yakov to stay because he was a source of Brachah. Why did Lavan take more animals than he should for his sons to watch?
Bechor Shor: He thought that [all] his property will be blessed as long as Yakov is around.
Perhaps his greed and lust for theft ("Mayim Genuvim Yimtaku"